Implantable Cartilage Created With Hybrid 3D Printer

While some hobbyists are rapidly prototyping items and objects from 3D printers, others in the medical field have taken that tool to a whole new level in printing out actual implantable tissue and even organs that could prolong life.

In the last few years, medical science has used 3D printers to replace damaged tissue (skin) or to restore limbs for those who have suffered wounds. While the procedures used so far are astounding in concept, they can't quite compare to what scientists from the Wake Forest Institute for Regenerative Medicine are developing using a hybrid 3D printer.

The group has recently made advances in simplifying the printing process for creating implantable cartilage-constructs that could be used to help regrow damaged cartilage in areas such as joints. This advancement was due in part by creating a hybrid 3D printer, which makes the overall process easier and is the combination of an ink jet printer and an electrospinning machine.

These two pieces of technology combined is the key to creating the cartilage-constructs as it combines both synthetic (for strength) and natural (gel used to promote healthy cell growth) materials. The scientists used the electrospinning machine to generate an electrical current through polymer solution to create very fine fibers. The process allows the scientists to control the composition of the polymers, which coalesce into porous structures and allows the cells to integrate into the surrounding tissue.

Click the image below for more images of the hybrid 3D printer fabricating implantable cartilage.

Wake Forest Institute for Regenerative Medicine used a hybrid 3D printer to fabricate implantable cartilage on the heels of printing a working kidney. (Source: Wake Forest Institute for Regenerative Medicine)

They tested their findings using layered flexible mats of electrospun polymer, which were combined with a solution of healthy rabbit ear cells deposited using the ink jet printer. The resulting constructs were then stress-tested for strength using variable weights, which were found to be robust and still alive after one week of testing. These constructs were then introduced into living mice in a controlled environment for two, four, and eight weeks to analyze how they would function in a living system. After eight weeks, the constructs developed the structures and properties of that of elastic cartilage, which is promising for use in human patients.

The Wake Forest scientists haven't limited their study and development to just cartilage. They are looking into developing bio-printing of dental implants, prosthetics, and organs, as well. According to the scientists, development of printing dental implants is progressing considerably. An implant can be fabricated using a digitized intra-oral scan to gain a blueprint of sorts, which can be emailed to a dental lab for precise printing of the patient's teeth. Not only is the process significantly cheaper, but it can be done quicker than any past method.

The same can be said for advancements in prosthetic limbs using 3D printing technology. Until recently, prosthetics were fabricated by shaving a piece of foam into the approximate form of a patient's limb and transformed into a mold where a polymer representation is then fabricated. This is not only time consuming, but also expensive, as well as painful to the recipient. Companies such as Bespoke Innovations have capitalized on this technology to custom print artificial limbs based upon the patient's dimensions. The company first interviews the customer to get an overall picture of their personality, such as interests, and can then manufacture a completely one-of-a-kind limb made from a myriad of materials, colors, and designs to suit the individual needs of the customer.

Increased developments in 3D printing technology for bio-printing soft-tissue organs are on the rise, as well. Several scientific institutions are developing methods to bio-print transplantable organs, but their core outcomes involved are relatively the same. The process of bio-printing organs starts with a culture of replacement tissue, which is taken directly from the patient. This culture is then printed layer by layer, which eventually becomes a three-dimensional structure. Recipients of the newly-printed organs have a reduced risk of their immune system rejecting the organ, as it's made from their own cells rather than using a replacement organ from a donor. While bio-printing technology is still in its infancy, there have been great strides in achieving the lofty goal. Wake Forest succeeded in printing fully functional miniature kidneys that were able to filter blood and produce diluted urine back in 2003. The scientists have since been trying to develop even more sophisticated miniature kidneys, as well as scaled versions of a heart, liver, and even a uterus in an effort to successfully bio-print full-sized organs in the future. This could lead to longer living as limbs and organs could be replaced on a regular basis through a system of interchangeable, organic parts.

It's amazing how many people are now getting knee and hip replacements, Liz. And it's great that such technologies are available. A couple of generations ago, those injuries got worse and people were crippled by them. Thanks to some serious engineering innovation in the past 30 years, people can now live pretty normal lives with replacement joints.

Good point, Jenn. I think it will be a long time before we see anything like this used in human surgery. Cadaver cartilage for knees is still a new field, with just a handful of doctors doing those operations. Given that, I would think that 3D-printed cartilage might be a long way off.

In this case, they printed the framework and grew the rest of it. But, making the support structure is vital, only 3D printing make for an easy build of complicated forms. A few years ago, someone received a manufactured throat based on similar tech. I am sure that person is very happy now. This type of tech should be explored further and improved, without a doubt.

Anything to better our lives. Imagine, pulverized a fiber, print a new one. It will happen.

Ah, I know the feeling! Due to my sporting ways over the years, I fear some kind of cartilage replacement is in my future...the joints are starting to go tweaky on me...and my father had two knees and a shoulder replaced. Good to see some of these advancements...maybe they will be ready by the time we need them!

Hi Elizabeth M, I didn't have any cartilage replaced, just trimmed to lessen the chance of a future tear. Don't know if any form of artificial material was even available back then. Oh, to be 23 years old again!

Hi Cabe--thanks for highlighting these developments. I read your article, then some earlier reports on the Wake Forest work and others, and I'm still unclear. It seems that at least some (many?) of the promising approaches for organs involve printing a frame or scaffold roughly the size/shape of what you want, then somehow applying a tissue mixture and getting it to grow. If all goes well, you end up with the tissue you want in the geometry your want.

Where I get confused is while 3D printing the scaffold makes sense and I can see that 3D printing is enabling amazing advances, in the 2nd step it doesn't really look like printing. It is more like "applying". Although they talk about an ink-jet printer it is unclear that the 2nd step is really very selective or 3D. The photos unfortunately don't change that conclusion--they appear to be dispensing not printing.

Can you shed any more light on the process details and exactly where 3D printing is helping/enabling?

Every time I read a story about something that has been 3D printed - from a person's jaw to an outfit debuting at fashion week - I am more and more amazed. My fear, however, is that these 3D-printed body parts are going to backfire. How safe are they really? And how are we to know for sure?

I agree, Dave. I, too, never took a biology class in college while studying engineering. Bioengineering used to be an engineer's route to medical school. Now it should be much more than that -- an important discipline unto itself.

This is very impressive, and a good example of why engineers should study biology. The last time I took a biology class was in 9th grade -- I managed to make it all the way through college and graduate school in engineering without learning much of anything about living things. This is a real problem, since so many of today's engineering innovations are either biomedical in nature or biologically-inspired.

I think the "gross" factor comes with the territory, to a certain extent; it's something that medical students have to learn to get over. Intellectually, I don't think there is anything "gruesome" about body parts being made on an assembly line, especially if they will help people to have a better life. But on an emotional/gut level, it does seem kind of creepy.

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